1. Field of the Invention
The present invention relates to an electrically assisted bicycle. Particularly the invention relates to regenerative braking of a motor as a drive source for driving a wheel of the electrically assisted bicycle.
2. Description of the Background Art
Electrically assisted bicycles are generally provided with a motor drive mechanism for auxiliarily driving a rear wheel by a motor and also have a power source section including a battery and the like for supplying the motor with electric power.
The electrically assisted bicycle disclosed in Japanese laid-open patent No. 2001-30974 is an example of the electrically assisted bicycles, which is provided with a motor for auxiliarily driving a rear wheel, a condenser for supplying the motor with a driving current, a brake lever operated by a driver on the bicycle, a brake mechanism for braking the rear wheel by human power transmitted from the brake lever, and a control circuit (electric circuit). When the brake lever is operated, the control circuit closes a circuit for supplying the motor with the driving current from the condenser and applies a regenerative current to the motor. Thereby the motor is regeneratively braked to act as a power generator, and the rear wheel is braked. The control circuit further switches circuits so that the power generated by the motor is stored in the condenser.
In the above-described conventional example, when the brake lever is operated, braking by the brake mechanism works at the same time as braking by the regenerative braking of the motor. For this reason, the rear wheel is abruptly braked, and therefore, the bicycle does not run stably.